<?php
// + == === <>
$a = [1, 2];
$b = [3, 4, 5, 6, 1, 2];
$c = [1, '2'];
echo '<pre>';
print_r($a + $b);
echo $a == $c;//1
echo $a === $c;//false
echo $a <> $b;//1
echo $a !== $c;//1
echo $a != $c;//false

//集合 并运算 交集运算
//并运算
$aa = [10, 20, 30];
$bb = [40, 50, 10, 20, 20];
// $cc = array_unique(array_merge($aa, $bb));//并去重
$cc = array_merge_recursive($aa, $bb);
print_r($cc);

//交集运算
$ee = array_intersect($aa, $bb);
print_r($ee);

//差运算
$dd = array_diff($aa, $bb); //
print_r($dd);